Coffee roaster



y 1953' Q -P. T. CLARY 2,639,133

COFFEE ROASTER Filed Aug. 26, 1949 I INVENTOR. Palrkrk Clary.

. ATTORNEY Patented May 19, 1953 UNITED STATES PATENT OFFICE COFFEEROASTER I Patrick T. Clary, Carnegie, Pa.

Application August 26, 1949, Serial No. 112,422

1 Claim. (01. 263-33) This invention relates to improvements in coffeeroasters and method of operating same.

In my prior Patent No. 2,017,892, of October 22, 1935, I have discloseda method of processing coffee by subjecting the coffee beans to thedirect heat of a flame from a burner and then spraying water on theheated beans, while confining the resultant steam in contact with thebeans to properly impregnate the latter.

I have now discovered that by circulating hot air through coffee, whileit is roasting, and in a closed system, out of contact with gas flamesand their products of combustion, the moisture and flavor of the coffeebeans can be preserved due to the retention of evolved moisture and themaintenance of a maximum' uniform heat in the roaster'by recyclingheated air therethrough, and without requiring addition of water to thesystem.

The improvements in processing coffee are made possible by the novelcoffee roasting apparatus herein, whose construction and use insure theproper conjoint roasting and moisture tempering of coffee beans, withoutthe addition of water and without exposing the roasting beans to thecontaminating effects of combustion gases.

It is, therefore, among the features of noveltyand advantage of thepresent invention, to provide an improved apparatus for roasting coffeebeans, and the like, in a closed system and out of contact with gasflames and their contaminating products of combustion; to roast coffeevbeans in a directly heated, closed chamber, while recycling heated air,at predetermined tempera-; tures, through the roasting chamber, andcontrolling the moisture content of the roasting beans, by the regulatedadmission of cold air to roasting chamber.

The above and other desirable features of novelty and advantage of thepresent inventionv will be more clearly understood by reference to theattached .drawings illustrating a preferred embodiment of the invention,and in which;

Fig. 1 is an elevation, partly in broken section,

gases into the flue formed by and between the. outer wall of theroasting chamber and its in sulated casing. At'the top'of the drumlflythe angle to form deflectors 33, 34, respectively.

These deflectors form slotted channels with and. between the drum l0 andthe inner wall 2| of casing 20 is conformed to receive and space 'a hotair heater 40. An insulated outer casing 50 houses the apparatus, aswill be described more in detail hereinafter.

The drum III is mounted for rotation and is driven by a drivingmechanism comprising a ring gear 60 in mesh with gear wheel 6 mounted ondriving shaft 62, which is driven by a suitablemotor, not shown. Aplurality of guiding and spacing rollers 63 have bearing engagement thedrum II], as shown.

Referring now to the details of the novel coffee roaster, the insulatedouter housing 50 comprises front and back Walls 5|, 52, side walls 53,'54 and.

top 55. Brackets 56 mounted on walls 5|, 52 above the floor level serveas supports for the ends of manifold of the gas burner. The casing 20comprises an inner shell 2|, lagged with" an outer insulating coating22. 4 The casing 20 ismounted on a pedestal 23 comprising elongatedangularly disposed walls 24 having flangedfeet 25. A base plate 26,provided with spaced air inlets 21, closes the chamber formed by thelegs 24, and is desirably mounted on the feet or legs. 25 as indicated.The plenum chamber 28, formed. between the angular walls 24 andapertured base 26, is provided with spaced bafiles 3|, 32 mounted onopposite sides of the burner 30, and continu ously therealong. The upperedges of the baffle plates or guides 3|, 3,2 are bent outwardly at anthe insulated casing 20. Referring more particularly to Fig. 2, it willbe seen that the plenum chamber 28 comprises an inner combustion chamberdefined by and between the baffles 3|, 32 and-- a pair of outer coolingchambers defined by andbetween the baffles and the angular sides of thepedestal support. It willbe noted that the .bafiles 3|, 32 are generallyarranged to split the incoming streams of air through openings 21 toform. an inner combustion air supply stream and two outer cooling airstreams. The combustion gases from burner 30, mixed with cooling air,will flow into 'the'space or flue 35 between the drum and the insulatingcasing 20, the spacing 35 forming: a split heating duct surrounding thedrum 1., The combustion gases flow over the surface of the drum, ascendupwardly to flow over and, 'around hot air heater 40, and thenceupwardly through vent 36 to the atmosphere. The vent 36. is providedwith a suitable damper 31, controlled;- by anysuitable lever mechanismdesignated gen erally by numeral 38..

with l The roaster drum I will comprise an imperforate continuous solidouter wall H and closed ends l2, 13. A plurality of lifting vanes I4 aremounted on the inside of the drum. The end wall I! of the drum isprovided with a suitable circular aperture [5, and the opposite end I3is provided with an aligned opening IS. A pair of angular flanges I! aresecured on the front of ends [2, l3 and extend approximately to theinside of walls 5|, 52, suflicient clearance beingleft to permit freerotation of the drum in. The flanges l'l effectively seal off theopenings in the ends of the drum and preclude admission of com bustiongases into or between the inner spaces of walls 5|, 52 and the ends ofthe drum.

A special feature of the invention herein is the hot air recirculatorysystem. This system, as illustrated, comprises the cylindrical heater4!], fitted with heat indicator 4|. A combination suction fan-blower 43is connected at the base of; the rear wall 52, of the casing and pipe'44 incorporating, slide valve 44. The blower discharge pipe46discharges into hot air heater 40 through a right angle bendincorporating a cold air inlet valve 41 and slide valve 48. The outletend of: the hot air heater discharges into the roaster, chamber belowthe spreader through duct 43,- as shown. The blower-43 is provided witha valved chaff dischargev line 43' and discharges into any suitablechaff container. as shown.

A spreader is disposed; within the roaster chamber, being mounted at oneend, on plate ll, securedto the end wall 52 of the casing. A pluralityof electric resistance heating elements 12, having current leads (3, T4,are mounted on the plate- H. and. subjacent the spreader 10. A screen.15 is securedunderneath and along the spreader 10 to forma ductdischarging into hot air return pipe 44. A pivoted filling andemptyinggate, or front door llis mounted on the front wall 5|. of thecasing and extends into the drum space.

The operation of the novel;system herein will now; be readily. apparent:In starting the first roast, the roasting cylinder. I0 should'be heatedvup .to 500 F., or more. To this end, the resistance heating. elementsllv are energizedto speed up theheating of the roaster to the propertemperature. The'spreader 10 is heated andserves toheat' upthe coffeebeans falling in contact therewith. While the coffee beans are flowinginto the cylinder the chaff slide valve 445 is opened, hot air valve 48closed, and coldair valve 4-1=and blower 43 are opened. When all thegreen beans arein the. cylinder, the. chaff discharge valve, the.blower, and. the cold. air valve are closed, the hot air valve 48isopened, the motor drive turned on, andtheheat is regulatedas required;a-check on the temperature being. made bymeans of I heat regulator 4|.Whenthe roasting operation is about finished, the heat is turned off,valved chaff line 43 blower 43, and cold air valve 41' are opened, hotair slide valve 48 is closed, and the-coffee is milled for twoor three.minutes. As a result, the roasted beans are polished and the chaffdischarged. The hot, roasted beans are then dischargedto a cooling an. pWith the roaster drum in rotation, the hot gases from the burner willflow over thesurfaces ofthe. roaster and then over the surface of thehot air. heater drum 40. Simultaneously with theexternal roasting, the.beans in the roasting. drum are. subjected. to. a. separate.recirculating stream of tempered, heated air. Air-is caused to flowthrough duct 49 into roasting chamber I I! through screen and outthrough pipe 44 to suction blower and hot air heater 40. The heated airis then recycled. It will be noted that the coffee is uniformly roastedby being heated directly from the walls of the cylinder l0 and by hotair passed in a closed cycle through the roasting chamber, thusmaintaining the coffee beans out of contact with contaminating productsof combustion fromthe heater. Furthermore, because of the heating actionby direct heat, coupled with a uniform positive flow of heated air, thecoffee beans are uniformly heated throughout the course of the roast-ingoperation, andtheheating drum is maintained as closely as is physicallypossible at a uniform temperature-instead'of being subjected to intenseheat in one area and a relatively low heat in other areas.

By the improved system herein, a uniform heat is maintained duringroasting, and all the moisture and. goodness of the coffee, in thebeanie;

retained. The air circulation is so devised; that when the air is turnedoff, in seconds the roast ing chamber will be filled; with steam. Whenthe air is turned on again, in a few seconds the moisture is rescrbed inthe bean, preserving, the

strength and essence of the coffee.

As noted above, during the course of the roast-- ing operation, theheating gases may be tempered by admission or amounts of cold air.Additionally, by. closing slide 44 andopening cold air valve 49, at theend of the roasting operation, the atmosphere in the.

roasting chamber and the coffee beans are substantially chilled,with-the resultant condensation of'moisture, and its resorbtion by thehot,

beans. The cold'air is. admitted into the roaster in suflicient amountto: check the roast and give,

the roaster time to judge. the finish. Improved construction and" modeof operation permits a rapid and efficient. handling of the roastedcoffee beans and their relatively fast discharge from the roaster to-thecooling pans, permitting prompt reloading-and return to the regularroasting. op,- erationcycle. will be energized at the start of theroasting to speed up the bringing of. the roaster up to roasting heat.feature, as the initial heating of the roasting drumis not effected toorapidlyby themain gas,

heating flame.

By the controlledadmission of. cold air tothc recirculating hot air, a.tempered product can beobtained and the. roasting operation, includingcooling and discharge of the roasted beans, can.

be expeditiously. effectedwithout requiring cooling equipment. By thespecialmounting of the spreader. 1 0 and subj oined electrical heating.elements, as well asoutletduct 44 and chaff dis.- chargeduct43:.placedupon plate 11, these elements are removable as an. entity.This novel unitary combinationof elements can be installed as a unit inpresent types of roasterswhere combined with the suction blower 43 andwith or without specialhot airheater 40. The operation of the presenttypes of roasterscan .be very much improvedas to speed of operation andthrough less material handling.

It will nowbe understood there has been provided a novel, apparatus forroasting coffee by. conjoint useof. external gas-firing andinternal.

hot air circulation whereby .the roasted coffeeis uniformlyroastedr and:cooled by. the controlled circulationiof; temperedchot. airandtheroasting.

incorporation of controlled- As noted, the electric heaters I2.

This is a particularly-advantageous.

of the coffee is carried out with a minimum of equipment and inappreciably reduced time.

I claim:

A, roaster for coifee beans and similar beanlike materials comprising anouter insulated housing, a rotary drum mounted for rotation in thehousing, an insulated casing about the drum, a burner manifold mountedat the bottom of the drum and longitudinally thereof, means for introducing combustion air to said burner and directing the products ofcombustion through the space between the rotary drum and the insulatedcasing, a second fixed drum mounted above the rotary drum, a secondinsulating casing surrounding and spaced from the fixed drum andcontinuous with the first insulated casing, means comprising a hot airpipe connecting the said rotary drum and the stationary drum, and meansfor discharging heated air from the said stationary drum to the rotarydrum and circulating same comprising a valved discharge line, cold airvalving means in said discharge line, a blower connecting said dischargeline and the rotary 6 drum, whereby the rotary drum and the stationaryhot air heater are directly heated by the products of combustion of theburner, and the coffee in the rotary drum is continuously heated by aseparate recycled stream of hot air.

PATRICK T. CLARY.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 849,581 Spencer Apr. 9, 1907 1,133,047 Limburg et al Mar. 13,1915 1,319,764 Fullard Oct. 28, 1919 1,453,312 Engel May 1, 19231,782,946 Talbutt et a1 Nov. 25, 1930 1,911,763 Meade May 30, 19331,991,190 Backer et a1 Feb. 12, 1935 2,033,169 Zeun Mar. 10, 19362,069,192 Behr et al Jan. 26, 1937 2,087,602 McCrosson July 20, 19372,129,673 Burns Sept. 13, 1938 2,443,620 Hubbard June 22, 1948

